Reputable projects such as prismarine-auth and azalea-auth hardcode the Nintendo Switch client ID instead of their own custom Azure application, so we should be fine to go ahead and do the same.
Unfortunately, client IDs created for custom Azure applications, such as Prism Launcher's client ID, will no longer work with Fjord Launcher, so users who manually supplied a client ID will need to clear theirs.
Seems to work correctly, I renamed my accounts.json file and re-added my MS account and it logs in fine, got the Login email from Microsoft saying "Minecraft for Nintendo Switch" as the application
Reputable projects such as prismarine-auth and azalea-auth hardcode the Nintendo Switch client ID instead of their own custom Azure application, so we should be fine to go ahead and do the same.
Unfortunately, client IDs created for custom Azure applications, such as Prism Launcher's client ID, will no longer work with Fjord Launcher, so users who manually supplied a client ID will need to clear theirs.